marine life in Cornwall

Tag Archives: Ceramium

Quick post about an hour worth of snorkelling on Wednesday. Very frustratingly, I had a housing mishap on Saturday, meaning my brandnew Olympus camera and lens got wet. $%&^”! as the saying goes…..I have sent both back for repair and hope all can be fixed relatively fast and cheap. A minor disaster but what can you do? Go out with my old Canon Powershot and wetlens instead I guess! The viz was not the greatest but I can only blame myself for a disappointing haul of photos. I took around 200 (as usual), whittled them down to 75 or so on my camera afterwards and then to 30 or so on my computer. Did some tweaking in ‘Photos’ afterwards but they were 5’s, 6’s and 7’s at most. The midshore pools were looking pretty. Lots of one of my favourite seaweed species Slender-beaded Coral Weed Jania rubens growing on top of (mostly) Hairy sandweed (and possibly Black scour weed). Lots of other epiphytic species grow on top of this assemblage, including Sea lettuce Ulva, Brown fan weed Dictyota dichotoma, Gelidium spp, Ceramium spp, Colpomenia OR Leathisia (I still am not sure of the difference..) and many others.

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Last week I went for a little swim at the usual spot at Castle Beach. The viz was nowhere near as good as last month, but still OK. There are schools of sand eels and sand smelt and I even saw an eel. The contrast between growing brown seaweeds and withering red seaweeds has become even greater. Below you see some yellowed Harpoonweed and a ‘forest’ of Thong weed covered in epiphytes.As the light was a bit subdued, I focused on the most shallow area. The bare parts of the rock are covered with barnacles, dog whelks, sting winkles and limpets. The seaweeds are mainly Serrated wrack Fucus serratus, Sea lettuce Ulva, Grape pip weed Mastocarpus stellatus, some Ceramium and Laver Palmaria palmata, as well as Dumont’s tubular weed Dumontia contorta.

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I have been diving three times last week but due to internet problems have not posted about them. I hope to do that in the coming days, but first wanted to blog about this mornings snorkel session in the shallow rock pools at Castle Beach in Falmouth, as I experienced the best viz (visibility) ever here. Apart from the stunning viz, I was very lucky with the fish: I spotted a Tompot blenny, Two-spot Gobies, Fifteen-spined stickleback, Rock goby, Pollack, Ballan-, Corkwing- and Goldsinny Wrasse and Sand eels (above and below). However, I mainly wanted to check what the seaweeds looked like, and things have definitely changed over the last month (see here).The Wireweed Sargassum muticum and Spaghetti (or Thong) weed Himanthalia elongata are thriving and at low tide hang over the surface creating ‘tunnels’. The Harpoonweed below is in decline, turning from pink to yellow-white (and the Bonnemaisonia is almost completely gone). The fronds of the False eyelash weed have turned from juicy and red-brown to wiry and yellow and the corraline algae are turning white. The Sea lettuce Ulva has died back and is covered in speckles (sporangia?). Some epiphytes are thriving, the very fuzzy brown Pylaiella littoralis covers kelp, a Ceramium species grows as pompoms on the Spaghettiweed. One pink and fuzzy species that is growing well I should have taken a closer look at because I am not sure what it is now (I will enquire at the Seaweeds of the NE Atlantic facebook group). The next species I think I can identify: Chipolataweed Scytosiphon lomentaria. The Bushy rainbow wrack Cystoseira tamariscifolia looks fuzzier and greyer than before. Although with less species and more subdued colours, the pools still look beautiful, and I hope the good visibility will last a bit longer!

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The last day of January I took an hour to explore a pool at the upper part of Castle Beach. The resulting shots turned out a lot better than they did the last time. As most of the pools are bare rock, there are no problems with sand/silt, but they are very shallow and on the receiving end of drainage pipes resulting in rain water mixing with the salt water, affecting visibility (this is not necessarily bad as it can make a photo more interesting). It was overcast and I did not experience problems with overexposure; I actually found that tweaking in Photoshop made the photos look worse. Below a Beadlet anemone Actinia equina, the most common anemone on rocky shores. They can be bright red or a drab brown (the green version is rare here) but have bright blue beadlets, or more technically acroraghi. These contain stinging nematocsysts used in territorial fights. After that a small Daisy anemone Cereus pedunculatus, which are usually more mottled in appearance (and not common here, or perhaps I do not know how to look for them…).Next up, a red growth which I should have investigated further, I am not even sure if it is a sponge or something else. After that, a worn Thick top shell Osilinus lineatus, a young Dumont’s tubular weed Dumontia contorta, a red Banded pincer weed Ceramium sp. happily producing oxygen and finally Patella limpets covered in Brown limpet paint Ralfsia verrucosa.

I have been a bit busy and so the photos below are some weeks old. The seaweeds are in decline already it seems. Actually, that is not true, there are plenty of seaweeds growing, but some of the prettier ones are dying off and some of the uglier ones are taking over. The window to take the nicest rock pool shots is quite short, pretty much early spring only. The ubiquitous False eyelash weed Calliblepharis jubata is yellowing, the green Sea lettuce Ulva lactuca is starting to cover everything and the Red grape weed is getting ‘fluffy’. Not the best session photo quality-wise and probably the last of the year. The Bushy rainbow wrack Cystoseira tamariscifolia is abundant and looking good (on the photo with Discoid forkweed Polyides rotundus) and I managed I nice shot of young Thong (or Spaghetti) weed Himanthalia elongata. I have done some more research into ‘proper’ underwater cameras and was tipped of about the Canon G16 (thanks Thomas from HydroMotion Media), maybe something for next year….The past couple of times when focusing on the seaweeds I also encountered some animals (it is hard not to). Many Snakelocks anemones Anemonia viridis, with some having very short tentacles. Next, a Decorator crab Macropodia rostrata covered in Banded pincer weed Ceramium. Mermaid’s purses (egg cases) of the Bull huss/Greater-spotted Dogfish/Large-spotted Catshark/Nursehound Scyliorhinus stellaris seem to be exclusively attached to Bushy rainbow wrack. Finally, a Stalked jellyfish Haliclystus octoradiatus on Wireweed Sargassum muticum.